This invention relates to agricultural combine harvester hydraulic systems and the mechanisms used to couple such a system to a harvesting assembly hydraulic system.
Agricultural combine harvesters are provided with harvesting assemblies at the front of the vehicles. The harvesting assemblies engage the crop in the field being harvested and direct the crop into the combine vehicle for processing. Various different harvesting assemblies can be coupled to the front of the combine so that different crops can be harvested. For example, a harvesting assembly known as a corn head includes snapping rolls which snap corn stalks downwardly, pulling the ears of corn from the stalk as the stalk is pulled downwardly. The ears are then transported by an auger toward the centerline of the combine. A conveyor mechanism within a feederhouse then transports the ears of corn upwardly and rearwardly proximate the centerline of the vehicle so they can be further processed within the main body of the combine.
The combine vehicle includes a hydraulic system that adjusts the speed of the feederhouse conveyor, auger and snapping rolls. A variable diameter sheave driven by the combine""s engine is provided for driving the conveyor. The diameter of the variable speed sheave is adjusted by a hydraulic cylinder that is fluidly coupled with the combine""s hydraulic system by way of a hydraulic line. Fluid flowing into or out of the hydraulic line adjusts the position of the hydraulic cylinder, thereby adjusting the effective diameter of the sheave. The speed of a drive belt that extends between the variable speed sheave and the conveyor is thereby adjusted, resulting in the speed of the conveyor being correspondingly adjusted. The auger and snapping rolls are operatively connected with and driven by the conveyor such that adjustment of the speed of the conveyor also causes the speed of operation of the auger and snapping rolls to be adjusted. The operator adjusts the speed of the conveyor, auger and snapping rolls in this manner by manipulating hydraulic system controls within the cab of the combine.
Another type of harvesting assembly is known as a cutting platform, which is used to harvest crops such as wheat. The cutting platform includes a cutter bar that cuts the wheat near the ground surface and a conveyor that transports the cut crop to the combine for separation of the grains of wheat from the rest of the plant. These cutting platforms include a reel that rotates about a horizontal and laterally extending axis. The reel gently directs the crop rearwardly against the cutter bar. A conveyor within the feederhouse transports the crop rearwardly to the interior of the combine vehicle for further processing. The position of the reel can be raised and lowered by a pair of hydraulic cylinders located at the outer ends of the reel. In conventional combines these reel height adjustment cylinders are supplied fluid by the combine hydraulic system.
When the harvesting assembly is changed from a corn head to a cutting platform, a portion of the hydraulic line that extends to the variable speed sheave is hydraulically disconnected and instead is hydraulically connected to the cutting platform""s hydraulic line that routes fluid to and from the reel height adjustment cylinders. With the cutting platform installed in this manner, the hydraulic cylinder that controls the position of the variable speed sheave is effectively cut off from the rest of the hydraulic circuit, thereby locking the hydraulic cylinder in a particular position. The variable speed sheave is thereby also locked in the corresponding position, which causes the conveyor, and the cutting platform cutter bar which is operatively connected to and driven by the conveyor, to operate at a corresponding fixed speed. When the variable speed sheave is hydraulically disconnected from the hydraulic system during installation of a cutting platform, the conveyor and cutter bar will often be set at a speed of operation that is undesirably fast for cutting platform operation. The operator needs to remember to lower the speed of the variable speed sheave prior to disconnecting it from the hydraulic system for changover to the cutting platform. If he forgets to do this, the cutter bar of the cutting platform will typically operate at an undesirably fast rate, causing undesirable vibration during operation. To slow the cutterbar and eliminate the vibrations after the cutting platform is installed, the operator must hydraulically detach the hydraulic line from the cutting platform and reconnect it to the hydraulic cylinder that adjusts the position of the variable speed sheave, and then use the hydraulic controls in the cab to shift that cylinder and adjust the position of the variable speed sheave. The operator can then again detach the hydraulic line and re-attach it to the cutting platform hydraulic lines that extend to the reel height adjustment cylinders. The disadvantage of this operation is that it interrupts harvesting operations and consumes an undesirable amount of time.
It would be desirable to provide an agricultural combine that reduces or eliminates the vibrations caused by operation of a cutting platform""s cutter bar at excessive speeds after changing the harvesting assembly from a corn head to a cutting platform. It would also be desirable to simplify the operation of changing the harvesting assembly from a corn head to a cutting platform, and to reduce the time required of the operator to make such a changeover.
The present invention provides a hydraulic system for a combine and harvesting assembly having a valve mechanism that automatically routes fluid from a combine hydraulic line to a harvesting assembly hydraulic line when the harvesting assembly line is coupled with the combine hydraulic line, and automatically routes fluid from the combine hydraulic line to a hydraulic cylinder that controls the position and speed of a variable speed sheave of a conveyor drive system when the harvesting assembly hydraulic line is detached from the combine hydraulic line. The valve mechanism also includes a relief valve that allows pressurized fluid from the hydraulic cylinder to flow back to the combine""s hydraulic system when the valve is routing fluid from the combine hydraulic line to the harvesting assembly hydraulic line. A multicoupler is provided that allows a plurality of hydraulic and electrical lines of the combine to be coupled simultaneously with a plurality of corresponding hydraulic and electrical lines of the harvesting assembly. The valve mechanism can be defined in the body of the combine portion of the multicoupler. The valve mechanism includes a shunt or passageway defined within the body of the combine half of the multicoupler. The passageway automatically opens in response to the harvesting assembly""s hydraulic line being detached from the combine hydraulic line. In this open configuration the shunt or passageway routes fluid from the combine hydraulic line to the hydraulic cylinder that adjusts the variable speed sheave. The passageway automatically closes in response to the harvesting assembly hydraulic line being attached to the combine hydraulic line.